The animated show, a funnier, friendlier spin-off from the acclaimed six-season The Clone Wars, revolves around a young goofball trainee Jedi called Ezra, a conman who joins rebels based on the starship Ghost.
Vanessa Marshall says she wept when she won the role.
Marshall, an experienced voice actress with around 100 TV and game titles to her name, voices the ship's owner, Hera Syndulla, a Twi'lek and the group's mother figure.
But when she first auditioned for the part, Marshall had no idea it had anything to do with Star Wars. Names and places had been deleted from her script, but something about it had her Star Wars senses tingling.
"It was called a 'wolf' project. I found elements in the script that made me think about the rebel alliance, but when I told my friends it was a Star Wars cartoon they thought I was crazy," she says.
"I got a call back and when I walked into the room there was a picture of my character on the wall, and I realised on the spot [it was for Star Wars]. When I got the role I wept. It's like a dream come true."
Marshall promises Rebels, which has received rave reviews since its US premiere and been renewed for a second season, is closer in tone to George Lucas' original trilogy, with plenty of lighter moments for younger fans.
"There's a lot of quick-fire banter, much like we saw between Han Solo and Luke and Leia. It embodies the pacing and the style of the original. That brings back memories for older viewers, and there's something that the kids instantly understand.
"People have been starving to death for new Star Wars material. It's filling a void."
Marshall has also discovered being involved in a Star Wars show delivers a different level of fanaticism from what she's used to. Sometimes she runs into fans in the aisle of her local supermarket.
"I have very quietly enjoyed Star Wars on my own [for most of my life]. Now, my life has changed completely. I now have friends all over the world. I feel like I have this instant connection with people.
"These people understand me, we believe together, and that's one of the greatest changes, just having a world of new friends."
She may have a much-loved toy collection at home, but Marshall refuses to use her role on Rebels as fan-girl leverage to find out what's going on in Abrams' highly anticipated new Star Wars film, the seventh, due out at the end of 2015.
"I don't want to know. I will always be a Star Wars fan, but I'm a professional actress. I'm so grateful to step into that arena and be part of something that's so much larger than anything I am or will be.
"It's one of the most important stories ever told."
TV preview
What: Star Wars Rebels: Spark of Rebellion
Where and when: TV2, 4.05pm, today.